Method and apparatus for transmitting/receiving uplink signal, and method and apparatus for transmitting/receiving downlink signal

A user equipment for transmitting an uplink signal in a wireless communication system, the user equipment comprising:

• a radio frequency (RF) unit;
• and
• a processor configured to control the RF unit,
• wherein the processor is further configured to:
• control the RF unit to receive, from a base station, machine type communication (MTC) group configuration information for a group of user equipments (MTC group),
• control the RF unit to receive, from the base station, a random access response physical downlink control channel (RA response PDCCH) corresponding to a random access preamble based on the MTC group configuration information and a random access response physical downlink shared channel (RA response PDSCH) based on the RA response PDCCH, with or without transmitting, by the user equipment, the random access preamble to the base station according to whether the user equipment is a primary user equipment of the MTC group or not,
• control the RF unit to transmit, to the base station, uplink data based on the RA response PDSCH,
• control the RF unit to receive, from the base station, a PDSCH carrying downlink feedback information for the MTC group (DL feedback PDSCH), and
• control the RF unit to retransmit, to the base station, the uplink data when acknowledgement/negative acknowledgement (ACK/NACK) information of the user equipment, included in the DL feedback PDSCH, indicates NACK.

A method for receiving, by a base station, an uplink signal in a wireless communication system, the method comprising:

• transmitting, by the base station to a group of user equipments (MTC group), machine type communication (MTC) group configuration information;
• receiving, by the base station from only a primary user equipment among the user equipments belonging to the MTC group, a random access preamble based on the MTC group configuration information;
• transmitting, by the base station to each user equipment belonging to the MTC group, a random access response physical downlink control channel (RA response PDCCH) corresponding to the random access preamble based on the MTC group configuration information and a random access response physical downlink shared channel (RA response PDSCH) based on the RA response PDCCH;
• receiving, by the base station from the MTC group, uplink data based on the RA response PDSCH;
• for the user equipment group;
• transmitting, by the base station to each user equipment belonging to the MTC group, a PDSCH carrying downlink feedback information for the MTC group;
• and
• receiving, by the base station, uplink data retransmitted by a user equipment (NACK user equipment), of which acknowledgement/negative acknowledgement (ACK/NACK) indicates NACK, among the user equipments belonging to the MTC group.

A base station for receiving an uplink signal in a wireless communication system, the base station comprising:

• a radio frequency (RF) unit;
• and
• a processor configured to control the RF unit,
• wherein the processor is further configured to:
• control the RF unit to transmit, to a group of user equipments (MTC group), machine type communication (MTC) group configuration information,
• control the RF unit to receive, from only a primary user equipment among the user equipments belonging to the MTC group, a random access preamble based on the MTC group configuration information,
• control the RF unit to transmit, to each user equipment belonging to the MTC group, a random access response physical downlink control channel (RA response PDCCH) corresponding to the random access preamble based on the MTC group configuration information and a random access response physical downlink shared channel (RA response PDSCH) based on the RA response PDCCH,
• control the RF unit to receive, from the MTC group, uplink data based on the RA response PDSCH),
• control the RF unit to transmit, to each user equipment belonging to the MTC group, a PDSCH carrying downlink feedback information for the MTC group, and
• control the RF unit to receive uplink data retransmitted by a user equipment (NACK user equipment), of which acknowledgement/negative acknowledgement (ACK/NACK) indicates NACK, among the user equipments belonging to the MTC group.